UCF or Savvy engine/trans skid will fit perfectly with your UCF extra clearance xfr case skid.
Why would you protect the trans but not the engine oil pan too.
I can't imagine why you would not use one of the two.
Off the top of my head, I don't know of any others that only protect the transmission, other than the factory one. I'm sure there might be, so maybe someone else can chime in.